The preliminary hearings for a 14-year-old Upper Macungie girl and her soldier boyfriend accused of killing the girl's mother because she wouldn't allow them to date was postponed Thursday.

Attorneys for Jamie Lynn Silvonek and Caleb G. Barnes, 21, of Fort Meade, Md., filed the request earlier this week, court officials said. A new date has not been scheduled.

The two are accused of killing Cheryl Silvonek, 54, in the driveway of her home at 1516 Randi Lane in Upper Macungie. Her body was found early March 15 in a shallow grave off a rural South Whitehall road.

Both are charged with homicide, abuse of a corpse, tampering with evidence and conspiracy. They are both being held in Lehigh County Jail without bail.

Last week, Lehigh County District Attorney Jim Martin said he will oppose a petition filed by Silvonek's attorney to have her moved to a juvenile facility. She is the youngest girl in Lehigh County history charged as an adult with homicide.

Barnes admitted he stabbed Cheryl Silvonek in the neck several times in her sport utility vehicle while it was parked in the driveway of the Silvonek home, police say in court records. Jamie Silvonek was in the rear seat, he told police.

Investigators this month released more than 75 text messages Silvonek and Barnes allegedly sent the day before the killing in which she pleaded that she wanted her mother dead because she would not allow them to be together. In one, she allegedly wrote "I want her gone."

The investigation also led to a witness who overheard Silvonek discuss killing her parents with Barnes on March 7, the day after her mother told her to end the relationship, police say.

Authorities say Jamie Silvonek met Barnes in October where she lied to him about her age, saying she was 17. He also asked him to lie to her mother about his age to make him appear younger.

Cheryl Silvonek found out his age when she first met him on March 6 and wanted them to end the relationship, authorities say.

Hours before the killing, Cheryl Silvonek had taken her daughter and Barnes to a concert in Scranton because she did not want them to go alone and because it was her last attempt to break up the relationship, authorities said.